Double beam electron discharge tube



Aug. 26, 1958- G. MOURIER DOUBLE BEAM ELECTRON nxscumcz: TUBE Filed Jan.i1, 195:;

5 She ets-Shet 1 1 958 G. MOURIER 2,849,643

DOUBLE BEAM ELECTRON nxscmcs: TUBE Filed Jan. 11, 1956 5 Sheets-Sheet 2Aug. 26,- 1958 G MOURIER DOUBLE BEAM ELECTRON DISCHARGE TUBE Filed Jan.11,1956

5 Sheets-Sheet 3 Aug 26, 1958 Filed Jan. 11, 1956 G. MOURIER 2,849,643

DOUBLE BEAM ELECTRON DISCHARGE TUBE 5 Sheets-Sheet 5 United StatesPatent DOUBLE BEAM ELECTRON DISCHARGE TUBE Georges Mourier, Paris,France, assignor to Coinpagnie Generals dc Telegraphie Sans Fil, acorporation of France The present invention relates to traveling waveand standing Wave electronic tubes, with bi-dimensional or bidirectionaldelay structures which have a geometrlcally periodicity along twoperpendicular or, more generally,

intersecting directions.

It is an object of the present invention to provide'a tube 1-, of thistype in which two beams, or group of beams, are

projected along two mutually intersecting directions for respectiveinteraction with wave components propagatmg along two dimensions of thedelay structure. Energy propagates in the delay structure either intraveling or in standing waves. Generally, the propagation takes placein traveling waves along at least one of the two directions considered.

The invention provides either oscillator or amplifier tubes.

The invention will be better understood from the ensuing descriptiontaken with reference to the appended drawing, wherein:

Fig. 1 is an explanatory diagram;

Fig. 2 shows diagrammatically the electrode arrangement of a tubeaccording to the invention;

Fig. 3 is an axial cross-section of an amplifying tube according to theinvention;

Fig. 4 shows the strapping diagram of the tube of Fig. 3;

Figs. 5, 6 and 7 show an oscillator tube according to the invention, invertical longitudinal, vertical transversal and horizontal longitudinalsections, respectively;

Figs. 8 and 9 show another embodiment of the oscillator tube accordingto the invention, in axial and transversal sections, respectively, Fig.9 alsoreferring to tube of Fig. 3;

Fig. 10 is the strapping diagram of the tube of Fig; 8.

The electrode arrangement of a tube according to the invention isdiagrammatically shown in Fig. 2. It is as sumed that an ultra highfrequency energy of a given frequency propagates in the delaystructure 1. As'the case 1 may be, this energy is either fed to thisstructure for amplification or is generated in the same, as in the caseof an Each channel is built up by a series of adjacent cells, 1

which are also coupled to each other and are diagrammatically shown inthe Fig. 2 as squares C.

A first cathode 2 extending in the direction 0y is positioned foremitting a first laminary electron beam 3, or a plurality of parallelbeams, in the direction Ox. This beam, after having followed a pathparallel to the delay in the directions Ox and Oy. This net 'E theelectrons of beam 6.

structure 1, is collected by a collector 4. A second cath ode 5,extending in the direction Ox, emits a second" laminary beam 6 in thedirection Oy. An output horn 7 is'coupled to the delay structure 1 alongitsedges parallel to cathode 5 and remote therefrom. As shown, this"horn comprises a well 8 extending in the direction 0y, and a wall 9substantially parallel to the arrows10, showing the assumed generalpropagation direction of' energy in structure 1. Wall 9 serves as acollector for Horn 7 is connected to an out put'wave guide 11. Theinclination of wall 9 is such 'as to match the horn to the structure 1.This inclination" is preferably selected, so that the matching occurs"substantially in the intermediate portion of the desired fre- 15 quencyband of the tube.

Delay structure 1, horn 7 and collector 4 are' brought to a commonpositive potential by a source 30. Catho'des 2 and 5 are brought, bysources 30 and 32 respectively, to negative potentials with respect tothis common potential. These potentials, which may be adjusted ormodulated, determine the respective velocities of the beams 3 and 6.

The wave, when propagating in the structure in any direction, undergoes,in each cell C, a phase shift (p, the respective components of which, inthe directions Ox and- Oy are ex and y. In the diagram of Fig. 1, taxhas been plotted on the abscissae and guy on the ordinates. By making aseries of measurements for a given frequency range, a set of curves P,such as that shown by way of ex ample, in Fig. 1, may be obtained forany given delay structure 1. Each curve F corresponds to a given frequency and may be termed an isofrequcncy curve. The co-ordinates of eachpoint of each of the curves F repre sent the respective phase shifts,along Ox and Oy, which a wave, having the frequency corresponding to thecurve onrwhich is located the point under consideration, undergoes ineach cell C of the delay structure 1. It will benoted that [the samefrequency may correspond to difierent phase shifts (px, or gay, i. e.for a given velocity of beam- 3,or 6, a great number of frequencies maybe obtained- In other words, if, in a tube having a delay structure '1,an electron beam -is projected-in the direction'Ox, this beam may' becaused to interact, either for amplification or oscillation purposes,with anyone of a great number of waves of various frequencies. If xhas-the-value OB, the beam 3 may interact with all the waves,-the frequencies of which correspond to the isofrequency =lines-= crossed by thestraight line BBIZL' In the case of the oscillator, this is, obviously,a cause of instability :and indetermination of the oscillationfrequency.Y

Of course, it isto be understood that theabove expla nation is onlypurported to give a broad understanding-of the physical phenomenonconcerned and that the applicant is not to any extent boundby,-or'-limited, tothis' explanation.

According to the invention,- two' electron beams normal to each otheror, more broadly, intersecting each-otheig-z are propagated forinteraction with'the energy propagating in the delay structure of theFig.2. Referring to the diagram of Fig.1, it may be seen that only-awavehaving a given frequency is able to interact with beams 3 and 6"simultaneously. In Fig. 1, this frequency is determined by the point ofintersectionD of line BBn-and line CCh parallel to the axis. OB and 0Care respectively equal to sex and aywhich correspond gation velocitiesof the beams 3 modifying-the velocity of one or the'other'beam; 30rd, orof'both at the same time,thus' causing' -point'D to ber' shifted in theplane of the diagram.

According to -the"knowii techniqueof the"traveliiig"" to the respectiveproga Y and. 6. Thereforef-the II frequency corresponding-to point D,may be adjusted-by" wave amplifier or oscillator tube, on one hand, orof the backward wave oscillator, known under the name of Carcinotron(registered trademark) on the other hand, the structure diagrammaticallyshown in Fig. 2 may be used to build up either an amplifier or anoscillator. In the case of an amplifier, a Wave of a given frequency isfed to the delay structure 1 and the velocity of beams 3 and 6 isadjusted to this frequency. In the case of an oscillator, the velocitiesof beams 3 and 6 determine the oscillation frequency. Of course, in eachcase, the tube, only a few components of which are shown in Pig. 2, mustcomprise the whole of the necessary structure in accordance with knowntechnique.

An amplifier according to the invention will now described.

Referring to the general diagram in Fig. 2, it is seen that the energyto be amplified may be fed to the structure 1 either in the direction ofcollector 4, or in the direction of collector 9. This energy propagatesin network 1 in any direction, determined only by the structure of thenetwork. As already mentioned, the respective velocities of beams 3 and6 must be adjusted so as to be, respectively, in synchronism with thecomponents of the wave to be amplified along the directions Ox and y.

An embodiment of an amplifier tube according to the invention is shown,by way of example, in axial crosssection in Fig. 3. The transversalsection of this tube is the same as that of the tube of Fig. 9.

In this example, the delay network 1 of Fig. 2 has been rolled up toform a cylinder, the generatrix of which is parallel to Ox. In this way,two opposed edges of structure 1 are coupled to each other and standingwaves are established in the direction of 0y, i. e. circularly in eachtransverse cross-section of the cylinder, whereas propagation in theaxial direction is effected in traveling waves. As shown, the networkcomprises an array of vanes 20, carried by the wall of a cylindricalmetal envelope 21. Thus, the network defines a wave guiding systemhaving a plurality of adjacent uniform and uniformly spaced parallelducts surrounding a central duct with which they communicate. Along theaxis thereof is located a cylindrical cathode carried by a sleeve 22,inside which is located the heating filament, whose ends protrude at theend 23. An axial magnetic field is produced by a coil 24. The fieldintensity is such that the electrons originating from cathode 5 havetheir respective paths sufl'iciently bent not to land on the vanes 20.As may be seen from Fig. 9, beam 6 of Fig. 1 is, in his case, formed byan electron cloud propagating around the axis of the tube and parallelto a cross-sectional plane i. e. in the direction Oy.

The tube comprises, in addition, several electron guns, three in theembodiment shown, 2', 2", 2", which project three parallel elementarybeams 3, 3", 3" focused in the direction Ox by the axial field formed bycoil 24. This group of beams is equivalent to beam 3 in Fig. 2. The gunsare fed by connections 25, and electrons, accelerated by anode 26connected to envelope 21, are projected into the space between cathode 5and vanes and collected by collector 4 at the end of their trajectory.

A number of vanes 27, located in an intermediate zone of the delaynetwork in the axial direction, are, according to a known technique,coated with an attenuating substance for the purposes well known in theart.

The tube is fed by sources 30 and 32 as in Fig. 2.

Cathode 5 extends between the end of the attenuated portion 27 and thecollector 4. Accordingly, the tube operates as a conventional travelingwave amplifier in the portion comprised between the input and one end ofthe attenuated portion 27, and as an amplifier according to theinvention between the other end of this portion and the output of thetube. The strapping system, shown in Fig. 4, comprises conductors 29respectively connected to all the vanes of the same row. The ends '4 ofconductors 29 alternatively connected, on one side, to one of theconductors of the pair of conductors 28, and, on the other side, to oneof the conductors of a pair of conductors 31. It is known that, in thisway, the propagation of direct space harmonics is promoted.

The energy to be amplified is fed to the input 28 of the tube and isextracted at the output 31. As shown, both the output and the input arein the form of bifilar lines connected to strapping 29.

Two oscillators according to the invention will now be considered by wayof example. It has already been mentioned that for a given velocity ofone of the beams, a plurality of oscillation frequencies may beobtained. The frequency of the oscillation produced is positivelyselected only when the propagation velocities of the two beams aredetermined.

Figs. 5 to 7 show a first embodiment of the oscillator according to theinvention. The bidirectional network 1 comprises a postively biasedelectrode plate 12 carrying parallel rows of fingers 13, and a planenegative electrode 14, electrically connected to cathode 2 and parallelto plate 12. Electrodes 2, 12 and 14 are carried by rods 15, sealed inthe insulating walls of envelope 16. These rods may serve as leads inconnections for the supply circuits. Cathode 2 is adapted to produce aplurality of parallel beams, forming together laminar beam 3. Theseelementary beams are projected between the rows of fingers 13. Collector4 of beam 3 is shaped as a metal block and is part of the vacuum tightenvelope E of the tube. The output wave-guide 11 is closed by aninsulating window 17. Pole pieces 18, 19 generate a magnetic field, thelines of force of which are parallel to the beam 3 and perpendicular tobeam 6. When a negative potential with respect to electrode 12 isapplied to electrode 14, an electric field perpendicular to the magneticfield is produced between these electrodes. This electric field isconcentrated between the end of fingers 13 and electrode 14'. It issubstantially zero in the spaces between the fingers. Thus, beam 3 isfocused by the magnetic field. Beam 6 propagates in the space comprisedbetween the ends of the fingers and electrode 14, normally to crossedelectric and magnetic fields. It is fed into this space by means of asuitable electronic optical device, of any known type, as is well knownin the art.

It should be noted that in the oscillator of Figs. 5 and 7 energypropagation may take place either in traveling waves in both directions,or in standing waves in both directions or in traveling waves in onedirection and in standing in the other.

If the oscillator is caused to operate with standing waves, reflectingmeans must be provided along the correspondlng edges of the delaystructure. For instance, if standlng wave energy is caused to interactwith beam 3, reflecting planes, diagrammatically shown by dash-lines atR and R in Fig. 7, should be provided. Similarly, planes Ra and R'acould be provided in the direction of the beam 6, or plane Ra could beprovided alone while the output should be substantially mismatched, theeffect being of course the same.

When energy is propagated in traveling waves the interaction could occureither in the direct or in the reverse mode. In the last case, absorbingmeans should be provided at the collector end of the beam in accord ancewith the practice described in a copending applicatron, Serial Number281,347, filed April 9, 1952, in the name of B. Epsztein, assigned tothe same assignee. Such absorbing means could be located in the vicinityof the inner face of block 4, as diagrammatically shown at A and B, inthe case of beam 3 and beam 6 respectively.

Of course, the tube, as shown, could be used as an amplifier with theenergy fed at 11' and extracted at 11. Whatever the operation of thetube may be the main feature remains the provision of an at leastbidimensional delay structure cooperating with at least two beams.

Figs. 8 and9 illustrate, respectively, in axial and transversal crosssections; a further embodiment of theoscillator according to theinvention. The design of this oscillator is broadly thesame as that ofthe amplifier in Fig. 3. However, there is, of course, no inputconnection provided. The output connection 31 is located in the vicinityof the cathodes 2, 2", 2". The end of the delay structure is attenuatedin the axial direction for the reasons pointed out above. Oscillationalong this direction, is by interaction of beams 3, 3", 3" with aninverse space harmonic. The bifilar output 31 is connected to strappingwires 29, the latter being connected according to the wiring diagram ofFig. 8, showing the array of vanes 20. Straps 29 are alternatelyconnected to the vane 20 of the twoadjoining rows. Experience shows thatthis strapping enhances the propagation of a strong inverse spaceharmonic;

The system formed by beams'3', 3", 3 and the delay structure operates asa backward wave oscillator;

The system formed by cathode 5 and the delay structure can be comparedto a magnetron. It is tightly coupled to output28 through straps 29, andit will behave as an amplifier with respect to the oscillationsgenerated by beams 3', 3" and 3".

As pointed out before, many other embodiments could be provided withoutdeparting from the scope and spirit of the invention, the essentialfeature being always the provision of an at least 'bi-dimensional delaystructure cooperating with at least two mutually intersecting beams.

In particular it is to be noted that three beams propagated in threeintersecting directions by means of a three dimensional delay structurecould be used. The operation of a tube provided with a threedimensional, or three directional, delay structure is basically the sameas the operation of a tube having a bi-dimensional structure.

The advantages of the invention may be summarized as follows:

It is an advantage to use a bi-dire'ctional delay structure because alarger beam current can be used than in a simple delay line.

The presence of a second electron beam increases the power and theefficiency.

The necessity of 'a second electron beam has been shown here when thefrequency is defined by the velocity of the beam or beams, i. e. whenthere is a distributed feedback through backward Wave operation.

If the frequency is defined by the circuit, i. e. when there arestanding waves in all directions, there will be a problem of modecompetition and the second beam will help to favor a desired mode;

If the amplifier of this application is compared to the amplifier ofcopending application, Serial No. 557,099, filed January 3, l956,'thesecond beam represents a way to obtain a sequence of gain according tothe direction of propagation inside the tube. Then attenuation can beused as in conventional traveling wave tubes, instead of having to useunidirectional, for example ferrite, attenuation.

If the amplifier according to this application is compared to aconventional traveling wave tube, it has the advantage of allowingmagnetron type interaction with the second beam, normal to thepropagation of energy, with the high efliciency that a magnetron isknown to have.

What is claimed is:

1. In an electron discharge tube, a delay transmission structure havingdistinct paths for: delayed energy to propagate therein in mutuallyintersecting directions, means for directing respectively distinct beamsof electrons along said paths to interact with energy therein, andoutput means coupled to said delay structure.

2. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyintersecting directions; first electron emissive means positioned forpropagating electrons in said first direction in coupled relationshipwith said structure for interaction with energy propagating therein;second electron emissive means positioned for propating electrons insaid second direction in coupled rela tionship with said structure forinteraction with energy propagating therein; and output means coupled tosaid structure for abstracting energy propagating therein.

3.An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyintersecting directions; first electron emissive means positioned forpropagating electrons in said first direction in coupled relationshipwith said structure for interaction with energy propagating therein;second electron emissive means positioned for propagating electrons insaid second direction in coupled relationship with said structure forinteraction with energy propagating therein; collector means forcollecting the electrons propagated along at least one of saiddirections; and output means coupled to said structure for collectingenergy propagating therein in at least one of said directions.

4. A tube accordingto' claim 2 wherein said output means comprisecollector means positioned for collecting electrons propagating in saidsecond direction.

5. An ultra high frequency discharge tube comprising: a delay structurewhichis' geometrically periodical along first and second mutuallyintersecting directions; first electron emissive means positioned forpropagating electrons in said first direction in coupled relationshipwith said structure for interaction with energy propagating therein;second electron emissive means positioned for propagating electronsinsaid second direction in coupled relationship with said structureforinteraction with energy propagating therein; means for propagating saidenergy in one of said directions in traveling waves; means forpropagating said energy in standing waves in the other of saiddirections, and output means coupled to said structure for abstractingenergy propagating therein at least in said one direction.

6. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second' mutuallyintersecting directions; first electron emissive means positioned forpropagating electrons in said first direction in coupled relationshipwith said structure for interaction with energy propagating therein;second electron emissive means positioned for propagating electrons insaid second direction in coupled relationship with said structure forinteraction with energy propagating therein; matching means for causingenergy to propagate in traveling waves along at least one of saiddirections and output means coupled 'to said structure for collectingenergy propagating therein.

7 An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyintersecting directions; input means for feeding energy to said delaystructure; first electron emissive means'positioned for propagatingelectrons in said first'direction in coupled relationship with saidstructure for interaction with energy propagating therein; secondelectron emissive means positioned for propagating electrons in saidsecond direction in coupled relationship with said-structure forinteraction with energy propagating therein; collector-means forcollecting the electrons propagated along at least one of saiddirections, and output means coupled tosaid structure for abstractingenergy propagatingutherein along at least said second direction. I

8} An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyintersecting directions; input means for feeding energy to saidstructure; first and second electron emissive means positioned forpropagating electrons respectively in said first and second directionsin coupled relationship with said structure for interaction with energyexisting therein; means for propagating energy in standing waves alongone of said directions; means for propagating said energy in travelingwaves along the other direction, and output means coupled to saidstructure for extracting energy propagating therein.

9. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyintersecting directions; input means for feeding energy to said delaystructure; first and second electron emissive means positioned forpropagating electrons respectively in said first and second directionsin coupled relationship with said structure for interaction with energyexisting therein; collector means for collecting electrons along one ofsaid directions; and output means for abstracting traveling wave energypropagating along at least one of said directions.

10. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyintersecting directions; first and second electron emissive meanspositioned for propagating electrons respectively in said first andsecond directions in coupled relationship with said structure forinteraction with energy existing therein; means for propagating saidenergy in standing waves along at least one of said directions and meansfor abstracting energy from said tube at least along one of saiddirections.

11. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyintersecting directions; first and second electron emissive meanspositioned for propagating electrons respectively in said first andsecond directions in coupled relationship with said structure forinteraction with energy existing therein; means for propagating saidenergy in traveling Waves along at least one of said directions; andoutput means for abstracting energy from said tube.

12. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyperpendicular directions; a plane electrode extending along said delaystructure; terminal connections for providing an electric field betweensaid delay structure and said electrode; first electron emissive meanspositioned for propagating electrons in said first direction; means forproviding a magnetic field normal to said electric field and parallel tosaid first direction; second electron emissive means positioned forpropagating electrons in said second direction; collector means forcollecting the electrons propagated along said first direction; andoutput means coupled to said structure for abstracting at least theenergy propagating along said second direction.

13. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyperpendicular directions and has its ends mutually uncoupled in saidfirst direction and mutually coupled in said second direction; firstelectron emissive means positioned for propagating electrons in saidfirst direction; means for providing a magnetic field having its linesof force extending in said first direction; second electron emissivemeans positioned for propagating electrons in said second directionunder the action of said magnetic field; collector means for collectingthe electrons propagated along said first direction; and output meanscoupled to said structure for abstracting at least the energypropagating along said first direction.

14. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyperpendicular .directions and has its ends mutually uncoupled in saidfirst direction and mutually coupled in said second direction, to form awave guiding system having a plurality of adjacent uniform and uniformlyspaced ducts surrounding a central duct and communicating therewith; anelongated cathode extending over at least a portion of said central ductfor emitting electrons; magnetic means directing said electrons alongsaid second direction; a plurality of cathodes positioned for emittingelectrons in said first direction; and output means coupled to saidstructure for abstracting at least the energy propagating therein alongsaid first direction.

15. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyperpendicular directions and has its ends mutually uncoupled in saidfirst direction and mutually coupled in said second direction, to form awave guiding system having a plurality of adjacent uniform and uniformlyspaced ducts surrounding a central duct and communicating therewith; anelongated cathode extending over at least a portion of said central ductfor emitting electrons; means for providing a magnetic field fordirecting said electrons along said second direction; a plurality ofcathodes positioned for emitting electrons in said second direction,said cathodes being positioned at one of the uncoupled ends of saidstructure and said elongated cathode extending from the other uncoupledend of said structure over at least half the length thereof; input meanscoupled to said structure at the end thereof adjacent to said pluralityof cathodes and output means coupled to said structure at the oppositeend thereof; and absorbing means in the ultra high frequency field ofsaid structure in the intermediate portions thereof.

16. An ultra high frequency discharge tube comprising: a delay structurewhich is geometrically periodical along first and second mutuallyperpendicular directions and has its ends mutually uncoupled in saidfirst direction and mutually coupled in said second direction to form awave guiding system having a plurality of adjacent uniform and uniformlyspaced ducts surrounding a central duct and communicating therewith; anelongated cathode extending over at least a portion of said central ductfor emitting electrons along said second direction; means for providinga magnetic field having its lines of force extending in said firstdirection for directing said electrons in said second direction; aplurality of cathodes positioned for emitting electrons in said firstdirection, said cathodes being positioned at one of the uncoupled endsof said structure and said elongated cathode extending from the same endof the structure over at least a portion thereof; output means coupledto said structure at the same end thereof; and absorbing means in theultra high frequency field of said structure at the opposed end thereof.

17. In an electron discharge tube, a delay transmission structure havingdistinct parts for delayed energy to propagate therein in differentdirections, two electron beam means, and means for propagating said twoelectron beam means in operative relationship with said delaytransmission structure to provide velocity components of said beam meansin said directions.

References Cited in the file of this patent UNITED STATES PATENTS

